The authors of this rich and interesting paper have done a fine service to the field of child language by bringing to the forefront the largely neglected topic of later language development. Major discourse-oriented studies including children beyond preschool age have been confined to oral production of narrative texts (Peterson & McCabe, 1983; Berman & Slobin, 1994; Hickmann, in press), and they all leave off at around age ten. The pathbreaking work of Labov (1972) did in fact consider the language of pre-adolescents and teenagers in explicitly linguistic terms, but this also concerned oral narratives without focusing on development. One important contribution of the present study, then, is to show that the progression from early school-age via middle childhood and on to adolescence and adulthood involves far more than merely increased vocabulary.